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Experimental investigations of internal energy dissipation during fracture of fiber-reinforced ultra-high-performance concrete

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Frontiers of Structural and Civil Engineering 2019年第1期13卷 190-200页

作者： Eric N.landis Roman kRAVCHUk Dmitry LOSHkOV Department of Civil &Environmental Engineering University of MaineOronoME 04469USA

Split-cylinder fracture of fiber-reinforced ultra-high-performance concrete (UHPC)was examined using two complementary techniques:X-ray computed tomography (CT)and acoustic emission (AE).Fifty-mm-diameter specimens of two different fiber types were scanned both before and after load *** the CT images,fiber orientation was evaluated to establish optimum and pessimum specimen orientations,at which fibers would have maximum and minimum effect,*** expected,fiber orientation affected both the peak load and the toughness of the specimen,with the optimum toughness being between 20% and 30%higher than the *** AE energy was also affected *** CT scans of the specimens were used to measure internal damage. Damage was quantified in terms of internal energy dissipation due to both matrix cracking and fiber pullout by using calibration measurements for *** results showed that fiber pullout was the dominant energy dissipation mechanism;however,the sum of the internal energy dissipation measured amounted to only 60% of the total energy dissipated by the specimens as measured by the net work of *** is postulated that localized compaction of the UHPC matrix as well as internal friction between fractured fragments makes up the balance of internal energy dissipation.

关键词： ultra-high-performance concrete concrete fracture X-ray computed tomography acoustic emission

Arthropods and biofuel production systems in North America

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Insect Science 2010年第3期17卷 220-236页

作者： Douglas A. landis Benjamin P. Werling Department of Entomology and Great Lakes Bioenergy Research Center 204 Center for Integrated Plant Systems Michigan State University East Lansing Michigan USA

Biomass harvest may eventually be conducted on over 100 000 000 ha of US crop and forest lands to meet federally-mandated targets for renewable biofuels. Such largescale land use changes could profoundly impact working landscapes and the arthropod communities that inhabit them. We review the literature on dedicated biofuel crops and biomass harvest from forests to look for commonalities in arthropod community responses. With expanded biofuel production, existing arthropod pests of biofuel crops will likely become more important and new pests will emerge. Beneficial arthropods will also be influenced by biofuel crop habitats, potentially altering the distribution of pollination and pest control services to the surrounding landscape. Production of biofuel crops including initial crop selection, genetic improvement, agronomic practices, and harvest regimes will also influence arthropod communities. In turn, arthropods will impact the productivity and species composition of biomass production systems. Some of these processes have the potential to cause landscape-level changes in arthropod community dynamics and insect- vectored plant diseases. Finally, changes in arthropod populations and their spatiotemporal distribution in the landscape will have impacts on consumers of insects at higher trophic levels, potentially influencing their population and community dynamics and producing feedbacks to arthropod communities. Given that dedicated biofuel crops and intensified biomass harvest from forests are still relatively uncommon in North America, as they increase, we anticipate ＇predictably unpredictable＇ shifts in arthropod communities and the ecosystem services and functions they support. We suggest that research on arthropod dynamics within biofuel crops, their spillover into adjacent habitats, and implications for the sustainability of working landscapes are critical topics for both basic and applied investigations.

关键词： biodiversity land use change pest management

A case for systemic environmental analysis of cultured meat

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Journal of Integrative Agriculture 2015年第2期14卷 249-254页

作者： Carolyn S Mattick Amy E landis Braden R Allenby University of Texas School of Public Health 1200 Hermann Pressler DriveHouston TX 77030 USA School of Sustainable Engineering and the Built Environment Arizona State UniversityTempe AZ PO Box 875306 USA

The environmental implications of cultured meat are profound. An anticipatory life cycle assessment of cultured meat published in 2011 suggested it could have a smaller impact than agricultural meat in all categories except energy consumption. As with most technologies, cultured meat will almost certainly be accompanied by unintended consequences as well as unforeseen costs and benefits that accrue disproportionately to different stakeholders. Uncertainty associated with new engineered products cannot be completely eliminated prior to introduction, but ongoing environmental assessments of the technologies as they advance can serve to reduce unforeseen risks. Given the pace at which tissue engineering is advancing, systemic assessments of the technology will be pivotal in mitigating unintended environmental consequences.

关键词： cultured meat in vitro meat factory-grown food anticipatory life cycle assessment systemic environmental implications of emerging technologies

EFFECT OF COMPOSITION AND PROCESSING CONDITION ON MICROSTRUCTURAL PROPERTIES AND DURABILITY OF FLUOROPOLYMER/ACRYLIC BLENDS

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Chinese Journal of Polymer Science 2009年第1期27卷 59-69页

作者： Derek L.Ho Forrest.A.landis Diep Nguyen National Institute of Standards and Technology (NIST) GaithersburgMDUSA Pennsylvania State University YorkPAUSA Illinois Institute of Technology ChicagoILUSA

Fluoropolymer blends have been widely used as binders for exterior coatings because of their excellent resistance to ultra-violet (UV) radiation as well as to many corrosive chemical *** is known that the fluorinated component usually has a lower glass transition temperature and easily crystallizes in the final structure depending upon the blend composition and sample annealing *** investigated the effect of blend composition and annealing process (slow and fast cooling) on the surface morpho...

关键词： AFM Confocal microscopy Crystallinity Surface morphology Small angle scattering UV exposure

Characteristics and distributions of atmospheric mercury emitted from anthropogenic sources in Guiyang, southwestern Chin

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Acta Geochimica 2016年第3期35卷 240-250页

作者： Xiaohang Xu Na Liu Matthew S.landis Xinbin Feng Guangle Qiu State key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081People's Republic of China University of Chinese Academy of Sciences Beijing 100049People's Republic of China US EPA Office of Research and DevelopmentResearchTriangle ParkDurhamNC 27709USA

Continuous measurements of speciated atmo- spheric mercury （Hg）, including gaseous elemental mer- cury （GEM）, particulate mercury （PHg）, and reactive gaseous mercury （RGM） were conducted in Guizhou Pro- vince, southwestern China. Guiyang Power Plant （GPP）, Guiyang Wujiang Cement Plant, Guizhou Aluminum Plant （GAP）, and Guiyang Forest Park （GFP） in Guiyang were selected as study sites. Automatic Atmospheric Mercury Speciation Analyzers （Tekran 2537A） were used for GEM analysis. PHg and RGM were simultaneously collected by a manual sampling system, including elutriator, coupler/ impactor, kCl-coated annular denuder, and a filter holder. Results show that different emission sources dominate different species of Hg. The highest average GEM value was 22.2 ±28.3 ng·m-3 and the lowest 6.1 ± 3.9 ng·m-3, from samples collected at GPP and GAP, respectively. The maximum average PHg was 1984.9 pg·m-3 and the mini- mum average 55.9 pg·m-3, also from GPP and GAP, respectively. Similarly, the highest average RGM of 68.8 pg·m-3 was measured at GPP, and the lowest level of 20.5 pg·m-3 was found at GAP. We conclude that coal combustion sources are still playing a key role in GEM; traffic contributes significantly to PHg; and domestic pol- lution dominates RGM.

关键词： Atmospheric mercury Speciation Anthropogenic sources GEM - PHg RGM

DETERMINING ADEQUATE INFORMATION FOR GREEN BUILDING OCCUPANT TRAINING MATERIALS

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Journal of Green Building 2009年第3期4卷 143-150页

作者： Deborah Steinberg Melissa Patchan Christian Schunn Amy landis Chatham University University of Pittsburgh

As knowledge of the built environment’s impact on resource and energy use increases,industry leaders are moving toward a healthier,more sustainable solution by building *** green buildings have the ability to improve occupant health and productivity,it is not clear what impact the behaviors of building occupants have on the *** systems and technologies in green buildings require building occupants to think and operate differently in their new green environment,otherwise risking not fully gaining the beneﬁts of the new *** new behaviors necessary to the success of the green building are not necessarily obvious or *** cannot simply be learned“on-the-job;”rather the transformation will require formal *** likely requires changing attitudes and beliefs in addition to building a robust understanding of new *** study sought to determine the amount of information neces-sary to change occupants’willingness to use new energy-efﬁcient behaviors not followed in the conventional *** empirical test comparing four versions of the same training,each with varying amounts and types of information was presented to three different populations:nursing staff of a green building,clinical staff of a green building,and nursing staff of a conventional *** show that knowledge of green building standards and the impact of energy saving behaviors are the information necessary to increase willingness to change ***,staff members of the new,green building are more willing to change behaviors than staff of the conventional building.

关键词： green building LEED workplace training occupant behavior sustainable behavior

DEVELOPING A FOCUS FOR GREEN BUILDING OCCUPANT TRAINING MATERIALS

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Journal of Green Building 2009年第2期4卷 175-184页

作者： Deborah Steinberg Melissa Patchan Christian Schunn Amy landis MLA Chatham University University of Pittsburgh

With the shift from conventional to green buildings a need emerges to train staff on how to work within ***-ing occupants control many of the green building technologies,which makes it necessary to educate occupants on the differences between using a green building versus a conventional building in order to secure the green building’s *** breadth of information that is necessary for an occupant to know in order to change their behaviors to be in accord with the high performing building they occupy makes it necessary to use a systematic method to reduce the in-formation provided in *** study employs a decision matrix approach as an objective means to narrow the focus of the training.A case study is used to implement the methods developed in this study.A focus group evaluated the effectiveness of the decision *** from the focus group showed that staff was active in waste reduction behaviors,but not in energy efﬁcient *** supported the outcome of the decision matrix inﬁnding relevant,necessary information for the training.

关键词： green building workplace training occupants sustainable behavior MCDM

RESIDENTIAL LIFE CYCLE ASSESSMENT MODELING: COMPARATIVE CASE STUDY OF INSULATING CONCRETE FORMS AND TRADITIONAL BUILDING MATERIALS

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Journal of Green Building 2010年第3期5卷 95-106页

作者： Neethi Rajagopalan Melissa M.Bilec Amy E.landis Department of Civil and Environmental Engineering University of Pittsburgh949 Benedum HallPittsburgh PA15261

Innovative,sustainable construction products are emerging in response to market *** potential product,insulating concrete forms(ICFs),offers possible advantages in energy and environmental performance when compared with traditional construction *** though ICFs are in part derived from a petroleum-based product,the benefits in the use phase outweigh the impacts of the raw material extraction and manufacturing *** paper quantitatively measures ICFs’performance through a comparative life cycle assessment of wall sections comprised of ICF and traditional *** life cycle stages included raw materials extraction and manufacturing,construction,use and end of life for a 2,450 square foot house in Pittsburgh,*** showed that even though building products such as ICFs are energy intensive to produce and thus have higher environmental impacts in the raw materials extraction and manufacturing phase,the use phase dominated in the life *** the use phase,the home constructed of ICFs consumed 20 percent less energy when compared to a traditional wood-frame *** results of the impact assessment show that ICFs have higher impacts over wood homes in most impact *** high impacts arise from the raw materials extraction and manufacturing phase of *** there are a number of embedded unit processes such as disposal of solid waste and transport of natural gas that contribute to this high impact and identifying the top unit process and substance contributors to the impact category is not *** different unit processes or impact assessment methods will yield dissimilar results and the tradeoffs associated with every building product should be considered after studying the entire life cycle in detail.

关键词： building products insulating concrete forms life cycle assessment environmental impacts

Chemical characterization and sources of PM2.5 at 12-h resolution in Guiyang, China

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Acta Geochimica 2018年第2期37卷 334-345页

作者： Longchao Liang Na Liu Matthew S. landis Xiaohang Xu Xinbin Feng Zhuo Chen Lihai Shang Guangle Qiu Guizhou University Guiyang 550025 China State key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550081 China Guizhou Normal University Guiyang 550001 China U.S. EPA Office of Research and Development Research Triangle Park Durham NC 27709 USA

The increasing emission of primary and gaseous precursors of secondarily formed atmospheric particulate matter due to continuing industrial development and urbanization are leading to an increased public awareness of environmental issues and human health risks in China. As part of a pilot study, 12-h integrated fine fraction particulate matter （PM2.5） filter samples were collected to chemically characterize and investigate the sources of ambient particulate matter in Guiyang City, Guizhou Province, southwestern China. Results showed that the 12-h integrated PM2.5 concentrations exhibited a daytime average of 51 ± 22 μg m^-3 （mean -4- standard deviation） with a range of 17-128 μg m^-3 and a nighttime average of 55 ± 32 μg m^-3 with a range of 4-186 μg m^-3. The 24-h integrated PM2.5 concentrations varied from 15 to 157 μg m^-3, with amean value of 53 ± 25 μg m^-3, which exceeded the 24-h PM2.5 standard of 35μg m^-3 set by USEPA, but was below the standard of 75 μg m^-3, set by China Ministry of Environmental Protection. Energy-dispersive X-ray fluorescence spectrometry （XRF） was applied to determine PM2.5 chemical element concentrations. The order of concentrations of heavy metals in PM2.5 were iron （Fe）〉 zinc （Zn）〉 manganese （Mn）〉 lead （Pb）〉 arsenic （As）〉 chromium （Cr）. The total concentration of 18 chemical elements was 13 ± 2 μg m^-3, accounting for 25% in PM2.5, which is comparable to other major cities in China, but much higher than cities outside of China.

关键词： Trace elements PM2.5 Source apportionment